Trigger pair



May 6, 1958 M. CANEPA TRIGGER PAIR 4 Filed April 1, 1955 A INVENTOR- M/CHELE CANE PA BY BY f-a f-/ A T TORNE Y5 United States Patent TRIGGER PAIR Michele Canepa, South Norwalk, Conn., assignor to Olivetti Corporation of America, New York, N. Y., a corporation of Massachusetts Application April 1, 1955, Serial No. 498,694

4 Claims. (Cl. 340-174) The present invention relates to triggering devices and more particularly to triggering devices utilizing the hysteresis characteristic of ferro-magnetic materials.

It is well known in the art that materials having a substantially rectangular hysteresis loop can be used with great advantage for switching or triggering. Presently known two-state magnetic storage devices comprise essentially a pair of input windings, a pair of output windings, and a pair of shift or advance windings. Thus, each core of such a magnetic storage device comprises a set of three windings: an input winding, an output winding and a shift winding.

The magnetic cores used in these storage devices are such that a certain minimum critical amount of magnetomotive force must be applied to a magnetic core to drive it from saturation in one polarity to saturation in the opposite polarity. When less than this magnetomotive force is applied, it may still change the saturation slightly but will not cause the core to saturate in the opposite polarity.

These devices must often be capable of producing at an output terminal an indication of an input signal and at another output terminal an indication that no prior input signal has been applied to the device. In other words, trigger pairs, when receiving an input signal 1, must produce at one output terminal at a later time the same signal 1, while a second output terminal does notproduce any output at all. On the other hand, when the input signal is 0, the first output terminal must now produce no signal while the second output terminal must now produce a signal 1. Thus, a trigger pair of the type described above will positively give an indication of the prior application, or not, of an input signal.

Up tothe present time, a triode was generally added to a magnetic element so as to obtain the above mentionedtype of trigger pairs. The introduction of a triode, however, created disadvantages such as the use of a relatively large number of vacuum tubes, thus causing a relatively large power consumption, poor reliability and a. life determined by the life of the vacuum tubes.

The triggering system of the present invention uses a smaller number of vacuum tubes than in prior types, thus improving the reliability, decreasing power consumption, lengthening the useful life of the system in which they are used and, furthermore, making the system easier to manufacture and, therefore, less costly.

Accordingly, one object of the present invention is the provision of means for reducing the number of vacuum tubes in trigger systems using ferromagnetic elements.

Another and more specific object of the present invention is the provision of means for reducing the number of tubes used in a trigger pair or flip-flop of ferromagnetic elements by one.

In the present invention, two ferromagnetic elements are used for each trigger pair. Each core is provided with four windings which may be called, respectively, the set winding, the advance winding, the reset winding and the output winding. The set winding corresponds to the input winding, and the two set windings of each trigger pair are connected in series. Similarly, the two advance windings and the two reset windings are, respectively, connected in series. The output windings, on the other hand, have separate output terminals, one of which will provide indication of the presence of a prior signal, While the other will provide indication of the absence of such a signal.

In the trigger pair of the present invention, the reset windings serve to set, for example, the first core to its 0 condition, while setting the second core to the 1 condition so that when an input pulse is applied through the set windings of the trigger pair of the present invention, the first core will go to saturation of the opposite polarity, that is, to a position which may be called 1, while the second core is brought back to its original position.

Thus, at the application of an advance or clear signal,

the first core is returned to the saturation of the origi-.

nal polarity, thus producing an output pulse; while the second core, being already in that original position at receipt of the advance winding pulse, will remain in saturation of that polarity and, therefore, will not produce an output signal at its output terminal.

If there has been no set signal, then the operation is the following: the reset windings will again bring the first core to its 0 condition, and the second core to its 1 condition. Since now there is no set signal, at the application of the advance signal, the first core remains in its original condition of 0 and, thus, its output winding will produce no output, while the second core will now be brought back to its original polarity and will produce an output signal at its output terminal to indicate that no set pulse had been received by the trigger pair.

From the above it can be seen that the function ofa fourth winding, referred to above as the reset winding, on each core of the trigger pair is to reset one core to a position which may be called the 0 position while setting at the same time the second core to a condition which may be called the 1 condition.

Thus, another and more specific object of the present invention is the provision of means for resetting a trigger pair so that one element of the trigger pair is set in an arbitrary position 0 while the other element of the trigger pair is set at a corresponding condition 1 prior to the introduction of input signals.

These and other objects of the present invention will become apparent in the following description when taken in conjunction with the drawings in which:

Figure 1 is a schematic diagram of the trigger pair of the present invention using ferromagnetic elements.

Figure 2 is a time graph for describing the operation of a trigger pair of the present invention when a set pulse is applied to its input.

Figure 3 is a time graph for describing the operatio of the trigger pair of the present invention when no set pulse is applied to its input.

Referring now to Figure 1 showing a trigger pair of the present invention, it will be seen that the trigger pair comprises two magnetic cores 10 and 11. Cores 10 I and 11 are made of a substance having a square hysteresis loop. It should be noted, of course, that the present invention is applicable also to cores which do not have a rectangular hysteresis loop as long as appropriate means are provided such as those shown in Patents Nos. 2,666,151 and 2,680,819.

Cores 10 and 11 are shown in Figure 1 as being ringshaped. Core 10 is provided with windings 12, 13, 14 and 15 where winding 12 is a reset coil, coil 13 is the set or input coil, coil 14 the output coil, and coil 15 the advance coil.

It should be noted that the direction of the reset and set currents i and 1' in Figure 1 are such and the coils 12 and 13 are so wound that the magnetic fluxes produced by windings 12 and 13 oppose each other. Advance winding 15 when-energized by current. i produces a flux opposing that. produced by winding 13' and, therefore, of the same polarity as that produced by winding. 12.

Coil 14, the output coil,.is wound so as to. obtain the proper output or, in other words, an output. voltage having the desired polarity. Quite similarly, core 11 is. provided with windings 22, 23, 24 and where coil 22' is the reset coil, coil 23 the set coil, coil 24 the. output coil and coil 25 the advance coil. It will-be noted that. here coils 23 and 25 produce fluxes. in the. same direction while coil 22 produces a flux in the. direction opposite to the fluxes produced by coils 23 and.25.

The output coil 24 is here again woundzin a direction such that a voltage having adesired. polarity isproduced. It should be noted that the two input. windings 13 and 23 are connected in series and. whilev one terminal is used for applying an input pulse, the other terminal 31 is; connected to ground. Similarly, the advance windings 15 and 25 are connected inseries, and one end of the series circuit is connected to a. terminal 32,v while the other side is connected to ground.

The reset windings 12 and 22 arev also connected in series, and their series combination is connected on. one end to a terminal 35 and on the other end; to ground.

' The output windings 14 and 24 are connected on one end to ground and on the other end to separate output terminals 36 and 37,. respectively.

It is now possible to describe, referring to Figures 2 and 3, the operation of the trigger. pair of the present invention. More particularly, referring first to Figure 2, which shows a schematic diagram of the windings of each core with the sequence. of operationsoccurring in that core, vertical line 40 represents the first core 10, while vertical line 41 represents the second core 11. The horizontal lines 42, 43 and 44 represent different time, that is, increasing time from 42 to 44.. where, for instance, the interval of time between 42 and 43 is the same as the interval from 43 to 44, and it is also the same interval between 44 and 42. For example, in one embodiment of the present invention, each of these intervals may correspond to 5 microseconds.

Also shown in Figure 2 are the outputs f and f obtainable from the output windings 14 and 24 of cores 10 and 11, respectively. The slanting lines at the intersection of the horizontal and vertical lines represent the direction of the magnetic flux in the cores 10 and. 11 with a convention that the magnetic flux is derived as the specular reflection of the currents.

More particularly,,itwi1l be here assumed for simplicity that a line such as 50, namely, one that. forms an angle with the horizontal line 43 in the direction shown of less than 90 corresponds to a magnetic flux in the specular direction in the core 10, while a line such as 51, which makes an angle with horizontal line 42 of more than 90, represents a magnetic flux in the assumed negative direction.

It will also be assumed that the magnetomotive forces applied to cores 10 and 11 are sufi'icient to bring the cores from saturation of one polarity to saturation of the opposite polarity when the magnetomotive forces applied are of the proper direction.

Referring first to core 10, that is to the vertical line 49 of Figure 2, at a certain time that we may call t a reset pulse is applied to terminal 35 so that the reset windings 12 and 22 condition the cores 10 and 11, respectively, to arbitrary conditions 0 and 1. At a. second time 1 if an input pulse is applied to terminal 30 of the set windings 13 and 23 as shown in Figure 2, core 10 is brought from the original condition 0 to a condition l. If at time t an advance pulse is applied, to terminal 32 of the advance windings 15 and 25, core 10 is brought back to its original saturation and an output pulse is produced A at terminal 36, an output pulse which in Figure 2 is denoted by f.

At the same time, the sequence for core 11 will be the following: at time t core 11 is brought to a condition of saturation which may be called 1. The application of a set pulse at time t as clearly seen also with reference to Figure 1, will bring back core 11 to'its original condition 0. When, therefore, at time t an advance pulse is applied to terminal 32 of advance windings 15 and 25, core 11 remains in the original saturation 0 and, therefore, no output appears at terminal 37 of output winding 24 of core 11.

When at time t no set pulse is introduced at terminal 30 of the trigger pair of the present invention, then the sequence shown in Figure 3 is obtained. Referring to Figure 3, at time t again a reset pulse is applied to reset windings 12 and 22 to condition the cores 10 and 11 to their respective initial conditions of O and 1.

When at time t no input pulse is applied to terminal 30, the cores 10 and 11 retain their saturation as produced by the previously applied reset pulse. When then at time an advance pulse is. applied. to terminal 32 as indicated in Figure 3, core 10 remains in the condition 0 since the fiux produced now is inthe same direction as the flux produced by the reset pulse, while core 11 is brought back to its condition 0 since. the flux produced by the advance pulse is of a polarity opposite. to that produced by the previously applied reset pulse. Thus, at time t no. output appears. at terminal 36 of output winding 14 of core-10 while an output voltage will now appear at the output terminal 37 of winding 24 of core 11' as indicated in Figure 3 where f is now equal to 1, while in Figure 2 f had been equal to 0.

It is easily seen from the above that through a trigger pair of the type .described it is possible to obtain at terminals 36 and 37 indications that a previous set pulse had been applied to the. cores 10 and 11. or indications that such a set pulse had not been previously applied to coresv 10 and 11.

In the above description a specific embodimentv of the present invention has been shown. Other modifications may be made by those skilled in the art without departing from the spirit and scope of the invention itself.

What I claim as new and desire to secure by Letters Patent. is:

1. A binary system capable of providing indications of the presence of a signal, or of its binary complement, comprising a pair of ferromagnetic elements having an approximately rectangular hysteresis loop, first winding means on each of said elements for causing saturation of one of said elements in one direction and saturation of. the second of saidelements in the opposite direction, second Winding means on each of said elements for applying a signal tosaid pair of elements whereby the application of said signal causes the first of said elements.to saturate in the direction opposite to the said one direction and causes the second of said elements to return to its original saturation, third winding means on each of said elements for returning the said first element to its original satuartion and maintaining said second element in that original saturation, output winding means on each of said elements, one of said output means being energized when said third means are energized and producing an indication of the prior energization of the other means, said second output means providing an output signal when said third means are energized if said second means had not been previously energized.

2. A binary system for producing an indication of the presence of a signal or of its binary complement comprising a pair of ferromagnetic cores having an approximately rectangular hysteresis loop, a set winding wound. on each of said cores, said set windings being connected in series, an advance winding also on each of said cores and being also connected in series, a reset winding on each of said cores also being connected in series, output windings on each of said cores for driving an output signal, said reset windings producing a flux in said first core opposite to that'produced by said set winding and in the same direction of the flux produced by said advance winding, said reset winding on said second core producing a flux in the opposite direction of the flux produced by said set and advance windings, the output winding of said first core being energized after application of a signal at said set winding, the said output winding of said second core being energized when no signal has been previously applied to said set winding.

3. A trigger pair arrangement comprising first and second ferromagnetic cores having a substantially rectangular hysteresis loop, each core being provided with a set winding, a reset winding, an advance winding and an output winding, means to apply input pulses serially to the set windings of said first and second cores, means to apply reset pulses serially to the reset windings of said first and second cores, means to apply advance pulses serially to the advance windings of said cores, and means to derive separate output pulses from the respective output windings of said first and second cores, said reset winding on the first core producing flux therein opposed to that produced by said set winding and in the same direction as that produced by said advance winding, said reset winding on the second core producing a flux in the opposite direction to the flux produced by said set and advance windings, the output winding on said first core being enering, the output winding on said second core Ibeing energized when no input pulse has been previously applied to said set winding.

4. A trigger pair arrangement comprising first and second ferromagnetic cores having a substantially rectangular hysteresis loop, each core being provided with a set winding, a reset winding, an advance winding, and an output winding, means to apply input pulses serially to the set windings of said first and second cores, means to apply reset pulses serially to the reset of windings of said first and second cores, means to apply advance pulses serially to the advance windings of said cores, and means to derive separate output pulses from the respective output windings of said first and second cores, said windings of said first core being wound in directions relative to each other at which said reset winding produces a flux in said first core in a direction opposing that produced by said set winding and in the same direction as the flux produced by said advance winding, said windings on said second core being wound in directions relative to each other at which said reset winding produces a flux in said second core in a direction opposing that produced by said set and advance windings.

References Cited in the file of this patent Saturable-core Reactors as Digital Computer Elements, J. G. Miles; published June 17, 1949, by the U. S. Navy Dept. Bureau of Ships and Engineering Research Assoc., pp. 38, 39 and 40. Copy in Div. 23 in the Patent gized after application of an input pulse at said set wind- Oflice.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noo 2,834,004 May 6, 1958 Michele Canepa It is herebj certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 65, strike out "the other means, said second output" and insert instead said second means, the other output Signed and sealed this 26th day of August 1958.,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,834,004 May 6, 1958 Michele Ganepa It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 65, strike out the other means, said second output" and insert instead said second means, the other output o Signed and sealed this 26th day of August 1958,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

